How to get body file content [duplicate]

Im trying to do an API Call using Laravel and php. In the body of this call, I have a binary file which is of pdf format.

My code is :

     /**
     * @param Request $request
     */
    public function transform(Request $request)
    {
        $pixUrl = env('PIX_TRANSFORM_FORMAT_URL');
        $pixKey = env('PIX_TRANSFORM_FORMAT_API_KEY');

        $file = $request->file('file');

        dd($file);

        $response = Http::withHeaders([
            'x-api-key' => $pixKey,
            'Content-Type' => 'application/pdf',
        ])
            ->attach('file', $file, 'file')
            ->post($pixUrl);
    }

Here’s my postman call :

enter image description here

But as you can see, the dump returns me a null value from the file I try to request. I do need to stay with “binary” method and not “multipart/form-data”. Do you have any idea on how to resolve this ?